Below ground structural members are well-known in the field of construction and a variety of different designs have been developed in an attempt to achieve efficient and economical construction while maintaining structural integrity. Such structural members must be designed to resist lateral forces associated with the surrounding soil as well as downward forces associated with a structure resting thereon. Particularly severe lateral forces are often associated with hydrostatic pressure being exerted against the outside of such structural members. For example, during periods of heavy rainfall, water may be forced against an underground structural member under great pressure. Basements typically have soil against the outside of one or more walls and are thereby particularly threatened by such lateral forces. Under sufficient pressure, cracks will form in the basement walls and allow water to seep into the basement. Also, parts of the basement walls are often displaced inwardly by the pressure. Finally, if the deflection is allowed to continue unabated, an entire basement wall may buckle and collapse with resultant damage to the structure supported thereon.
It is well-known to use concrete blocks or cinder blocks for constructing basement walls. Although building codes currently in force in many jurisdictions prohibit such masonry block walls below ground, the practice is still followed in some areas. Consequently, many houses in existence today and some new housing have basement walls constructed of such masonry blocks. Although generally less expensive than equivalent poured concrete basement walls, masonry block walls are less resistant to lateral forces associated with the surrounding earth because the mortar joints binding the individual blocks are inherently weak in tension. A lateral force against the outside surface of a basement wall creates a compressive force component along the outside surface and a tensile force component along the inside wall surface. Therefore, as the mortor joints yield to the tensile force component, cracks appear between the masonry blocks on the inside wall surface.
One method of straightening walls may be seen in the Hevner U.S. Pat. No. 377,940. This method for redistributing the compressive forces in a wall includes using wedges to prevent further buckling. To practice such method however, requires that the outside of the wall below ground be exposed for placing the wedges. The Wertz U.S. Pat. No. 2,128,480 discloses a method of reconstructing concrete utilizing a concrete patch reinforced with a mesh network attached to the old concrete by tension anchor bolts but requires the removal of substantial portions of a wall surface to a depth sufficient to anchor the reinforcing mesh within the new concrete patch. A filling for and method of closing fractures in masonry walls is shown in the Walter U.S. Pat. No. 2,417,026. However, the material inserted into the cracks is yieldable to conform to further widening of the gaps and therefore would not bind the individual masonry units together sufficiently to resist additional separation.
Another heretofore common repair method involves replacement of the damaged masonry block walls. For a basement wall supporting a structure, the procedure usually involves raising the structure and placing temporary support posts thereunder. The earth adjacent the outer wall surface generally must be excavated to allow removal of the old masonry blocks and to allow a new wall to be constructed. Such excavation process typically results in large piles of dirt on the premises and damage to landscaping and shrubbery adjacent to the structure. The new basement walls are usually constructed with masonry blocks in the same manner as the old walls and therefore have the same inherent faults and are just as vulnerable to lateral hydrostatic pressure. This method of repair by constructing replacement masonry block walls not only leads to recurrences of the problems of leakage, displacement and eventual collapse, but is also time consuming and expensive.
The Johnson et al U.S. Pat. No. 4,189,891 shows a method for anchoring and straightening walls which includes digging a hole at some distance from the wall to be repaired. A threaded shaft is then inserted through the wall and the surrounding earth and into the hole where it is anchored in place. A wall plate is fitted over the end of the shaft extending through the basement wall and a nut is threaded thereon and tightened so that the wall plate is forced against the wall to thereby straighten and anchor the wall. However, there are several disadvantages to this method. First, the amount of force which can be exerted against the basement wall is limited by the condition of the surrounding soil which must securely anchor one end of the shaft. Secondly, exterior excavation is required to form the necessary outside holes. Finally, the wall plate and the end of the shaft and nut protrude inwardly from the basement wall. The owner of the structure may therefore have to construct another wall surface inwardly of the original basement wall to achieve a finished appearance.